// ONLINE [ Site Reliability Engineer ] [ Senior Software Engineer ] [ Tech Lead ]

Eiji Kudo

Eiji Kudo
"Motivation comes first"

Tech Lead, Senior Software Engineer, and SRE at TORIHADA Inc., working on FANME.
Leading system design for services used by several million monthly users and handling thousands of requests per second, across infrastructure, backend, and frontend.

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01

About

  • Living by the motto "Motivation comes first," I aim to boost the drive of both myself and my team members
  • Rather than forcing "correct" opinions, I move team development forward by suggesting things others might not know about in areas they want to explore
  • I love business. I strive to understand at the business level, proposing and implementing features with realistic effort estimates
  • I work by clearly defining expected milestones, completed tasks, in-progress tasks, and uncertainties
  • Keio University, B.E. in Computer Science
  • English: TOEIC 915 / TOEFL iBT 95
  • Licensed Real Estate Transaction Specialist
02

Experience

01

Designing Highly Available Infrastructure at Scale

Led the design of EKS and ECS runtime platforms serving several million monthly users and handling thousands of requests per second. Used HPA, Cluster Autoscaler, load testing, and database connection budgets to define safe scaling limits and pre-scaling plans, maintaining availability during traffic spikes of roughly 1,000 times normal levels.

Led stakeholder alignment, budget approval, and the zero-downtime migration of multiple production services from EKS to ECS as the business phase and operating model evolved.

Reduced infrastructure operations and management labour costs by roughly 80%, and combined AWS, GCP, and Datadog cloud and monitoring spend by roughly 50% through continuous usage analysis and resource right-sizing.

02

Scaling Delivery with Type Safety, Automated QA & CI/CD

Revamped the development and release platform, increasing deployments per engineer by roughly four times and reducing deployment lead time by roughly 30%.

Led product-wide type-safety improvements, including automatically generating typed frontend HTTP clients from backend type definitions.

Established automated testing and AI-driven E2E testing, along with AI usage guidelines, implementation standards, and an agreed review workflow, reducing QA and review effort while improving maintainability.

03

Designing, Building & Scaling AI Coding Infrastructure Across the Team

Codified project-specific coding conventions, architectural design intent, and prohibited patterns in AGENTS.md. Documented both abstract principles and concrete rules, building a foundation that enables AI to make appropriate decisions even in unfamiliar cases.

Designed and implemented 25+ Custom Skills to automate PR review, planning, and quality check phases. Built a skill suite covering the entire development cycle — including parallel critical PR analysis by specialised reviewers, exhaustive similar-issue detection, QA checklist generation, and sequential lint → type check → test execution with auto-fix.

Built infrastructure to auto-deploy isolated preview environments per PR for rapid verification of AI-generated PRs. Reviewers can start validation by simply accessing a URL, enabling simultaneous verification of multiple AI-generated PRs.

04

Designing & Building Backend Systems with Managed Services

Built a shared asynchronous processing platform spanning infrastructure and application code, combining queues and Redis according to workload requirements to move high-load and long-running work out of synchronous request paths.

Standardised retries and error handling so workloads could recover automatically from transient failures, then enabled the wider team to apply the same patterns consistently.

03

Skills

$ backend:

Quarkus Hono NestJS Ruby on Rails Laravel

$ frontend:

React Router Next.js (App Router) Next.js (Pages Router) TanStack Router

$ mobile:

React Native (Expo) React Native (Vanilla)

$ sre:

AWS EKS ECS Kubernetes Docker Terraform ArgoCD Datadog

$ languages:

TypeScript Kotlin Ruby Python C Java PHP
04

Past Works

Security AI Agent Platform

Full-stack

Design and development of a security platform providing AI-powered targeted attack simulations and personalised training. Schema-driven development with Zod OpenAPI for type-safe frontend-backend communication including error handling. Designed with Clean Architecture and DDD.

Hono React TanStack Router AWS ECS
Creator Job Matching Platform

Creator Job Matching Platform

Full-stack

A matching app connecting creators with business opportunities. Used by 5,000–10,000 users.

React Native Expo Firebase Ruby on Rails AWS
Beauty EC App

Beauty EC App

Full-stack

EC app with influencer reviews. Multiple payment methods including PayPay and convenience store payments.

React Native Expo Ruby on Rails (Spree) Zod TanStack Query

CareerMine

Full-stack

Job change support app. Implemented LINE/Firebase OAuth integration and interview application features.

React Native Ruby on Rails AWS

Job Hunting Etiquette Navi

Full-stack

Job hunting etiquette media site. Implemented both frontend and backend.

Next.js App Router Ruby on Rails WordPress CMS

SPI Exam Prep App

Full-stack

SPI exam preparation web app. Implemented user registration.

Next.js Pages Router Ruby on Rails

Construction Management Job App

Full-stack (solo)

A job search and career support app for specialised engineers.

React Native Firebase (Firestore)

Construction Exam Prep App

Tech Lead & Management

Past exam practice app for 2nd-class Building Construction Management Engineer. Registration, answering, and weak-point features.

React Native Firebase (Firestore)

Internal Shared UI Library

Lead

Built a shared UI component library with Storybook for internal use. Hosted on GitHub Pages.

Storybook React Hook Form Zod
05

Contact

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Detailed CV available!

Feel free to reach out via email or DM. I look forward to hearing from you!

If you have any work I can help with, feel free to reach out!

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